Fully Printed Wearable Vital Sensor for Human Pulse Rate Monitoring using Ferroelectric Polymer

The ability to monitor subtle changes in vital and arterial signals using flexible devices attached to the human skin can be valuable for the detection of various health conditions such as cardiovascular disease. Conventional Si device technologies are being utilised in traditional clinical systems; however, its fabrication is not easy owing to the difficulties in adapting to conventional processes. Here, we present the development of a fully printed, wearable, ferroelectric-polymer vital sensor for monitoring the human pulse wave/rate on the skin. This vital sensor is compact, thin, sufficiently flexible, and conforms to the skin while providing high pressure sensitivity, fast response time, superior operational stability, and excellent mechanical fatigue properties. Moreover, the vital sensor is connected to a communication amplifier circuit for monitoring the pulse waves with a wireless sensing system. This sensor system can realise the development of new healthcare devices for wearable sensor applications.

Endothelial function in subjects with isolated low HDL cholesterol: role of nitric oxide and circulating progenitor cells

Epidemiologic studies have shown that a low level of high-density lipoprotein (HDL) cholesterol is a risk factor for cardiovascular diseases. The purpose of this study was to determine the contribution of isolated low HDL cholesterol to endothelial function. Thirty-nine subjects with low HDL cholesterol who had no other cardiovascular risk factors were selected from the 5,417 participants from our population. We evaluated flow-mediated vasodilation (FMD) before and after 4 wk of treatment with the HMG-CoA reductase inhibitor pravastatin in 29 of the 39 subjects with isolated low HDL cholesterol. FMD was lower in the low-HDL-cholesterol group (n = 29) than in the control group (n = 29), whereas NTG-induced vasodilation was similar in the two groups. Pravastatin increased HDL cholesterol, urinary excretion of nitrite/nitrate, circulating levels of progenitor cells, and cell migration response to vascular endothelial growth factor in 15 subjects with low HDL cholesterol but not in 14 placebo control subjects. FMD increased in the pravastatin treatment group but not in the control group. NTG-induced vasodilation was similar before and after 4 wk of treatment in the two groups. Multiple regression analysis revealed that changes in HDL cholesterol, the number of progenitor cells, and migration of progenitor cells were independent predictors of augmentation of FMD with pravastatin. These findings suggest that low HDL cholesterol is an independent risk factor for endothelial dysfunction and that pravastatin improves endothelial function in individuals with isolated low HDL cholesterol through, at least in part, an increase in circulating progenitor cells.

Fluvastatin Alters Platelet Aggregability in Patients With Hypercholesterolemia

BACKGROUND

Hypercholesterolemia enhances platelet aggregability. Statins have beneficial effects on cardiovascular events. The purpose of this study is to investigate whether statins inhibit platelet aggregation and, if so, the mechanisms.

METHODS AND RESULTS

Twelve patients with hypercholesterolemia were prospectively randomized in a crossover design to receive either fluvastatin (20 mg/d) or colestimide (3000 mg/d) for 12 weeks. The subjects were switched to the opposite arm for additional 12 weeks. Before and after first and second treatments, experiments were performed. Eleven age-matched volunteers with normal lipid profiles served as controls. ADP-induced platelet aggregation, platelet-derive nitric oxide (PDNO) release, intraplatelet levels of GSH and GSSG, and intraplatelet nitrotyrosine production during platelet aggregation were measured. Fluvastatin and colestimide equally lowered total and low density lipoprotein cholesterol levels in hypercholesterolemia. Platelet aggregation was greater in hypercholesterolemia than in normocholesterolemia before treatment and was altered by fluvastatin. PDNO release, intraplatelet glutathione level, and GSH/GSSG ratio were lower in hypercholesterolemia than in normocholesterolemia before treatment and were increased by fluvastatin. Intraplatelet nitrotyrosine formation was greater in hypercholesterolemia than in normocholesterolemia, and decreased by fluvastatin. Colestimide did not have such effects. In vitro application of fluvastatin dose-dependently inhibited platelet aggregation. Furthermore, in vitro application of fluvastatin dose-dependently inhibited platelet nitrotyrosine expressions and the inhibitory effects by fluvastatin were reversed by preincubation with geranylgeranylpyrophosphate.

CONCLUSIONS

Fluvastatin altered platelet aggregability in hypercholesterolemic patients in a cholesterol-lowering independent manner, which was partly mediated by the improvement of intraplatelet redox imbalance.

Polymorphonuclear Leukocytes May Impair Endothelial Function

Objectives— To examine whether polymorphonuclear leukocytes (PMNs) in hypercholesterolemia (HC) are activated to generate large amount of superoxide in vivo and hence impair endothelial function and, if so, whether statins, which possess anti-inflammatory properties, may restore PMN-mediated endothelial dysfunction.

Methods and Results— At baseline, subjects with HC showed impaired endothelial function ( P <0.001), estimated by flow-mediated vasodilation of the brachial artery, and increased susceptibility of low-density lipoprotein (LDL) to oxidation ( P <0.0001) compared with control subjects. PMNs obtained from HC produced greater amount of superoxide ( P <0.0001), showed higher adhesiveness to cultured endothelial cells (HUVECs) ( P <0.0001), and impaired endothelial nitric oxide synthase (eNOS) Ser 1177 phosphorylation of HUVECs compared with controls ( P <0.001). Crossover administration of fluvastatin or colestimide for 3 months lowered LDL to the same levels ( P <0.001 for both). Endothelial function was restored ( P <0.0001). LDL oxidation ( P <0.0001) and superoxide release from PMNs ( P <0.0001) were diminished only in fluvastatin but not in colestimide arm. Fluvastatin attenuated PMN adhesion to HUVECs ( P <0.0001) and restored eNOS Ser 1177 phosphorylation of HUVECs ( P <0.001).

Conclusion— Statins may improve endothelial function at least in part by inactivating neutrophils independently of LDL reduction. Our results raise a novel concept that polymorphonuclear leukocytes may attack endothelia and play a pivotal role in the pathogenesis of atherosclerosis.

Uptake of oxidized low-density lipoprotein in a THP-1 cell line lacking scavenger receptor A

We previously isolated THP-1 subtype cells (sTHP-1), a cell line that expresses scanty amounts of scavenger receptor A (ScR-A) and does not undergo foam cell formation when incubated with acetylated low-density lipoprotein (Ac-LDL). In this study, we investigated the accumulation of esterified cholesterol in sTHP-1 cells incubated with oxidized LDL (Ox-LDL), a physiologically modified lipoprotein in human. While sTHP-1 cells incubated with Ac-LDL accumulated only small amounts of esterified cholesterol, those incubated with Ox-LDL accumulated amounts similar to those accumulated by parent THP-1 (pTHP-1) cells. sTHP-1 cells expressed CD36 in amounts similar to the amounts expressed by pTHP-1 cells, and Ox-LDL was internalized through this CD36. The amount of accumulated esterified cholesterol was 73-81% of that accumulated in pTHP-1 cells expressing ScR-A. The levels of 125I-Ox-LDL binding, association, and degradation in sTHP-1 cells were 64-70% of the corresponding levels in pTHP-1 cells. In our experiments utilizing ScR-A-deficient sTHP-1 cells and a specific antibody against human CD36, most of the Ox-LDL interacted with the CD36 receptor. In addition, a substantial amount of Ox-LDL (28-42%) was bound and degraded by sTHP-1 macrophages when both of the two major scavenger receptors, ScR-A and CD36, were deficient or blocked. These results indicate that CD36 in macrophages plays an important role in foam cell formation by Ox-LDL, while additional scavenger receptor(s) may take part in significant pathways of Ox-LDL uptake in macrophages.

Acquisition of secretion of transforming growth factor-beta 1 leads to autonomous suppression of scavenger receptor activity in a monocyte-macrophage cell line, THP-1

Macrophage cells derived from the human monocytic leukemia cell line, THP-1, accumulate esterified cholesterol when cultivated in the presence of acetylated low density lipoprotein (Ac-LDL) through scavenger receptors (ScR). In the present study, we isolated a subtype of THP-1 cells that failed to accumulate esterified cholesterol when cultivated in the presence of Ac-LDL. The cells had negligible amounts of cell association and degradation of Ac-LDL compared with the parent THP-1 cells. The subtype THP-1 cells did not express ScR mRNA as well as that of lipoprotein lipase. In contrast, the expression of apolipoprotein E mRNA was greater than that found in parent THP-1 cells. The culture medium of subtype THP-1 cells treated with 12-O-tetradecanoylphorbol-13-acetate inhibited the uptake of Ac-LDL and the expression of ScR in parent THP-1 cells. After a 48-h incubation in the culture medium containing 12-O-tetradecanoylphorbol-13-acetate, the culture medium of differentiated subtype THP-1 cells contained 6.9 ng/ml transforming growth factor (TGF)-beta 1, while that of parent THP-1 cells secreted below detection level, which was less than 3 ng/ml. This inhibitory effect of the conditioned medium on the expression of ScR in parent THP-1 cells was abolished by pretreatment of the culture medium with anti-TGF-beta 1 antibodies. Parent THP-1 cells expressed as much TGF-beta 1 mRNA as sTHP-1 cells after stimulation of differentiation. Although the precursor forms of TGF-beta 1 that were synthesized in both parent and subtype THP-1 cells were of similar size and were expressed at similar levels, latent TGF-beta 1-binding protein, which is necessary for the secretion of TGF-beta 1, could only be co-immunoprecipitated with anti-TGF-beta 1 antibody from subtype THP-1 cells. This suggests that subtype THP-1 cells secrete TGF-beta 1 into the medium by forming a functional complex with the latent TGF-beta 1-binding protein. We conclude that subtype THP-1 cells could not take up Ac-LDL because ScR was inhibited (leading to a loss of function) caused by the secreted TGF-beta 1.